The present invention relates to envelopes and more particularly to security envelopes or bags that impede tampering after the envelope had been closed and/or that indicate to the recipient that tampering had occurred after the envelope had been closed. These envelopes have particular utility in the transportation and handling of valuable items such as paper currency, checks, and other documents of value. Because of the enormous number of shipments of these types of documents arriving daily at banks and other entities for processing, it is common for the respective recipient entity to standardize the transport envelope used to convey documents and things to such recipient entity. For example, a bank normally purchases thousands of envelopes of the same design and supplies them to its customers to use in shipping money and documents to such bank. The outside of the envelope normally bears indicia prompting the sender to write the name of the sender, its account number with the bank, and the contents or total values within the envelope in cash, checks, and other documents.
Because of the nature of the transaction, once the recipient opens the envelope, the recipient becomes liable for any shortfall in the monetary contents placed in the bag by the sender. Consequently, the recipient has the duty to examine an arriving envelope carefully for any signs of tampering and either refuse to accept or return to sender unopened an envelope bearing signs of tampering.
Improvements have been made to envelope materials and designs to facilitate visual detection of safety envelopes of this nature. These prior improvements include (1) forming the envelope of high shear, impact resistant material that folds in half and enables heat sealing of two side edges other than the mouth of the envelope, (2) employing a tamper evident sealing strip that overlies the envelope flap that closes the envelope mouth, the seal having indicia that is supposed to distort upon tampering, which distortion is said to be easily discernible by the recipient upon visual inspection or (3) employing a closing system two vertically displaced sealing strip arrangement, the first to seal the mouth cover flap firmly to the envelope outer surface and the second to seal over the flap free transverse edge to the envelope outer surface and show tamper evidence if the second seal is tampered with and the flap edge is lifted. See U.S. Pat. Nos. 4,082,880, 4,483,018, 4,932,791, and 5,077,001, incorporated herein by reference, for examples of prior designs and purported envelope improvements.
Another known safety envelope, depicted in FIGS. 8-10, includes a series of laterally spaced openings 1 on the envelope front panel 3 near the envelope mouth or lip. A layer of adhesive 2 is located laterally across the inner surface of the back panel 4 opposite openings 1. Header 5 includes section 6 secured to the outer upper surface of back panel 4 by adhesive layer 8 and a section 7 extending beyond the top of panel 4.
A release liner 9 overlies layers 2 and 8. Header 5 is made relatively thick and consists of polyethylene material. Also, the bottom of layer 8 is equal with or above the bottom of layer 3. The user places the contents in the envelope, removes release liner 9, folds header 5 over to a dotted line printed on the front panel so that the free edge of layer 8 lies at or above the bottom of layer 2 and presses the parts together thus forcing layer 2 in contact with layer 8 through openings 1. Parts of layers 2 and 8 also adhere to the inner and outer surfaces of panel 3.
Notwithstanding prior designs, tampering continues to be a major problem with all known safety bags or envelopes. For example, successful tampering has been practiced on tamper indicating envelopes by a variety of commonly available products.
Tampering techniques include applying cold gas or fluids to the outer plastic surfaces of sealing flaps and plastic strips across all or a part of the envelope mouth. Such gas is readily available from commonly purchased consumer products such as aerosol spray cans and the like. When chilled, the adhesive becomes brittle and temporarily loses its adhering properties. The flap or strip is then opened, contents removed and flaps re-closed when the adhesive reaches room temperature. Those known bags with plastic breakable or tearable sealing means can be simply reinforced with plastic adhesive tape until they are resealed at or near room temperature. Once resealed, the tape can be simply removed.
Other techniques include using heat from a common hair dryer, a very sharp knife or pointed blade edge, or by simply peeling back the protecting flap or layer very slowly and carefully and doctoring any visual indicator that may arise. Solvents and long thin tools have also been used to defeat the envelope integrity.